Residence, Medication Key Factors Linked to Heatstroke-Related Deaths

Action Points

Explain to interested patients that certain factors may increase their risk of dying from heatstroke including living in an institution and taking high blood pressure medicine.

Explain to interested patients that there may be things they can do to help reduce the risk of dying from heatstroke including having an air conditioner at home or visiting places that are air-conditioned and engaging in frequent social activities.

LYON, France, Aug. 13 -- Residence in a nursing home and taking antihypertensive medications are among the factors that increase the risk of death following heatstroke, investigators here found.

Among 83 patients admitted for heatstroke, 58% died within 28 days and 71% died within two years, reported Laurent Argaud, M.D., Ph.D., of Hospices Civils de Lyon and University Claude Bernard Lyon I, in the Aug. 13 issue of Archives of Internal Medicine.

Half of the 48 patients who died within 28 days of hospital admission came from a nursing home or retirement home, compared with just seven of the 35 patients who were still alive two years after developing heatstroke (P=0.005), Dr. Argaud and colleagues found.

And 33 of the 48 were on antihypertensive therapy, compared with 13 of the 35 survivors (P=0.004). Patients who died were also more likely to be taking phenothiazines.

In a six-study meta-analysis published in the same issue, being confined to bed (OR, 6.44; 95% CI, 4.5-9-2), not leaving home on a daily basis (OR 3.35; 95% CI, 1.6-6.9), and not being able to take care of oneself (OR 2.97; 95% CI, 1.8-4.8) were all associated with a heightened risk of death after heatstroke.

The first study evaluated risks among patients treated for heatstroke at an inner city university hospital during the European heat wave of August 2003.

Patients who presented to the hospital with a fever of 41 degrees C or higher and/or had respiratory, cardiovascular or kidney dysfunction had greater risk of mortality early on, the researchers found.

Being in a coma at admission also increased mortality risk. Specifically, 81% of patients who died presented in a coma compared with 23% of the survivors (P=<0.001).

In addition, 23% of patients who died from heatstroke were anuric upon presentation. By contrast, none of the patients who survived heat stroke were anuric (P=<0.001).

Twenty seven patients were alive after one year and 24 were still alive after two years. But the patients who survived showed dramatic changes in their functional status one and two years after their bout of heatstroke.

The meta-analysis showed that patients who had working air conditioners in their homes (P<0.001), visited cool air-conditioned environments (P<0.001), and had more social contacts (P<0.01) fared better than their counterparts who had none of these escapes from the heat. Patients who took extra showers or baths and used fans seemed to have a lower risk of death, the investigators noted, but this trend was not significant.

These findings "provide a basis for potential risk-reducing interventions in the setting of heat waves," the authors noted.

None of the authors of either study report any conflicts of interest or funding.

Reviewed by Zalman S. Agus, MD Emeritus Professor at the University of Pennsylvania School of Medicine